CRAVEN College conservation management lecturer Gillian Thom extols the virtues of having a pond

THIS evening I opened the door to a chorus of croaks, signalling the spring return of frogs to my pond. For a few weeks, their croaking which is loud enough to be heard across the street attracts not only frogs but people to my front garden.

Only yesterday I returned to find a row of ten-year-old boys leaning over the wall fascinated and as I write I can see a pensioner leaning over and gazing at the pond. It’s quite a sight - as well as the noise, there are at least 20 frogs clambering over each other and filling the pond with spawn, which within months will turn into unbelievable numbers of tadpoles.

My pond is only small but it is amazing how much pleasure it has brought to my family and passers-by. When we initially dug the pond we added a few native plants but then decided to wait and see what arrived. Within the first year we had water boatmen and diving beetles and since then as well as frogs we have attracted damsel flies, ramshorn snails and in the last few years newts and newtpoles (newt tadpoles). This shows that, however, small and isolated your pond is, the creatures will find it and move in.

So garden ponds can be a great source of pleasure but are they important in the grand scheme of things? The answer is a definitive yes. According to the Freshwater Habitats Trust over 50 per cent of UK ponds have been lost in the 20th century and of those that remain over 80 per cent have been damaged by pollution.

Where have all these ponds gone? Many have been built over, drained or are no longer needed. In this area we had mill ponds and ponds maintained for animals to drink from, while in other areas, such as Norfolk, the ponds were the result of digging for marl to spread on the fields. This loss of habitat has had a severe impact on the hundreds of plants and wildlife associated with them.

As if pollution and physical loss were not enough to contend with there is the growing threat posed by invasive non-native species. Many invasive plants are associated with ponds and waterways and when introduced they can rapidly take over, for example floating pennywort can grow up to 20 centimetres a day smothering everything in its path. Many of these plants have been introduced through the horticultural industry and it is vital that garden pond plants (ideally native) are purchased from a reputable supplier. In addition any vegetation removed from ponds should be left by the side for a day to allow any creatures to return to the pond and then composted. As well as plants there are two diseases, Ranavirus and Chytridiomycosi, that are killing our frogs. These can be spread by moving frogspawn and frogs between ponds or by failing to thoroughly clean equipment such as wellies and nets.

There is no precise definition of a pond but it usually includes any seasonal or permanent water body between one metre to two hectares (about three football pitches) in size. Whatever, their size all clean ponds are wildlife havens and a great introduction to nature.

I volunteered for many years with Skipton Wildlife Watch and the pond dipping sessions were always our most popular events with adults and children alike – in fact we often had to remind the dads that their children needed a turn. Dipping is a very simple activity, all you need is a net, a tray and an identification key and if you want to see the invertebrates in all their magnificent glory a pot with a magnifying lid.

There are several online survey packs such as the Big Pond Dip run by the Freshwater Habitats Trust or OPAL’s pond survey both of which provide detailed instructions and identification charts and allow you to enter your results online. These results are collated nationally and give a detailed insight into the health of our ponds and because different creatures can tolerate different levels of pollution you can even calculate how clean the water is.

Pond dipping is safe and enjoyable as long as children are carefully supervised and hands are washed thoroughly before leaving, just remember to obtain permission and wash all of your equipment between sites. If you lack confidence or access to a pond, keep an eye out, there are sure to be pond dipping events in the early summer. Even better build a pond for wildlife this Easter, it doesn’t need to be very big mine is only 1.2m but as I hope you can tell it has provided my family with hours of pleasure.